server.py

import socket
import threading
import queue

messages=queue.Queue()
clients=[]

server=socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
server.bind(("localhost", 9999))

def recieve():
    while True:
        try:
            message, addr=server.recvfrom(1024)
            messages.put((message,addr))
        except:
            pass

def broadcast():
    while True:
        while not messages.empty():
            message,addr=messages.get()
            print(message.decode())
            if addr not in clients:
                clients.append(addr)
            for client in clients:
                try:
                    if message.decode().startswith("SIGNUP_TAG:"):
                        name=message.decode()[message.decode().index(".")+1:]
                        server.sendto(f"{name} joined!".encode(), client)
                    else:
                        server.sendto(message,client)
                except:
                    clients.remove(client)

t1=threading.Thread(target=recieve)
t2=threading.Thread(target=broadcast)

t1.start()
t2.start()